In a number of industries, vehicles or other transportation methods are used to pick up loads from one location and deliver the loads to another location. An exemplary industry that works within this model is the mining industry, in which material transportation involves a mining machine picking up a load of ore from a loading tool and transporting that ore to a processor. Additionally, processed ore may need to be transported to another site for additional processing. Because of this, material transport is an important aspect in the mining industry and can represent a large percentage of costs associated with mining.
A dispatching system for controlling the usage of mining machines within a mine can be used to optimize material transport and reduce costs. The essence of a dispatching system is to determine, every time a mining machine leaves a location in the mine, where the “best” place is for that mining machine to go. Determining the “best” place for the mining machine to go involves optimizing an objective, such as, for example, maximizing the overall production of the mine or minimizing hauling distances.
Two approaches have typically been used for dispatching systems—single-stage and multi-stage. Single-stage systems dispatch mining machines according to one or several criteria. However, single-stage systems do not take into account any production targets or constraints. Single-stage systems are often heuristic, or non-mathematical, rules to determine the mining machine assignments. Multi-stage systems, on the other hand, divide dispatching problems into multiple stages. Typically, multi-stage systems include an upper stage, which consists of calculating a production plan that optimizes use of mining equipment, and a lower stage, which consists of calculating individual assignments according to the restrictions and assignment groups in usage and according to deviations from the production plan. However, the production plan implies the most productive paths (i.e., shortest paths) are returned in the optimal solution.
U.S. Pat. No. 6,741,921 to Cohen et al. discloses a system and method for providing dispatch assignments to a plurality of vehicles in an environment including a plurality of sources and a plurality of processing sites. A production plan is determined based on environment information and optimal criteria. Based on the production plan and consideration of a cooperative assignment and/or anticipated future environment conditions, a dispatch assignment is selected for each vehicle.